drivers/clk/sunxi/clk-sun6i-apb0.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2014 Free Electrons
   4  *
   5  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
   6  *
   7  * Allwinner A31 APB0 clock driver
   8  */
   9
  10 #include <linux/clk-provider.h>
  11 #include <linux/init.h>
  12 #include <linux/of.h>
  13 #include <linux/platform_device.h>
  14
  15 /*
  16  * The APB0 clk has a configurable divisor.
  17  *
  18  * We must use a clk_div_table and not a regular power of 2
  19  * divisor here, because the first 2 values divide the clock
  20  * by 2.
  21  */
  22 static const struct clk_div_table sun6i_a31_apb0_divs[] = {
  23         { .val = 0, .div = 2, },
  24         { .val = 1, .div = 2, },
  25         { .val = 2, .div = 4, },
  26         { .val = 3, .div = 8, },
  27         { /* sentinel */ },
  28 };
  29
  30 static int sun6i_a31_apb0_clk_probe(struct platform_device *pdev)
  31 {
  32         struct device_node *np = pdev->dev.of_node;
  33         const char *clk_name = np->name;
  34         const char *clk_parent;
  35         struct resource *r;
  36         void __iomem *reg;
  37         struct clk *clk;
  38
  39         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  40         reg = devm_ioremap_resource(&pdev->dev, r);
  41         if (IS_ERR(reg))
  42                 return PTR_ERR(reg);
  43
  44         clk_parent = of_clk_get_parent_name(np, 0);
  45         if (!clk_parent)
  46                 return -EINVAL;
  47
  48         of_property_read_string(np, "clock-output-names", &clk_name);
  49
  50         clk = clk_register_divider_table(&pdev->dev, clk_name, clk_parent,
  51                                          0, reg, 0, 2, 0, sun6i_a31_apb0_divs,
  52                                          NULL);
  53         if (IS_ERR(clk))
  54                 return PTR_ERR(clk);
  55
  56         return of_clk_add_provider(np, of_clk_src_simple_get, clk);
  57 }
  58
  59 static const struct of_device_id sun6i_a31_apb0_clk_dt_ids[] = {
  60         { .compatible = "allwinner,sun6i-a31-apb0-clk" },
  61         { /* sentinel */ }
  62 };
  63
  64 static struct platform_driver sun6i_a31_apb0_clk_driver = {
  65         .driver = {
  66                 .name = "sun6i-a31-apb0-clk",
  67                 .of_match_table = sun6i_a31_apb0_clk_dt_ids,
  68         },
  69         .probe = sun6i_a31_apb0_clk_probe,
  70 };
  71 builtin_platform_driver(sun6i_a31_apb0_clk_driver);